Transfer and comminuting device



Dec. 22, 1959 Filed Feb. 14, 1955 c. H. NORDELL 2,918,171

TRANSFER AND COMMINUTING DEVICE 5 Sheets-Sheet 1 3 Sheets-Sheet 2 Filed Feb. 14. 1955 fipedAM Dec. 22, 1959 c. H. NORDELL TRANSFER AND COMMINUTING DEVICE 3 Sheets-Sheet 3 $0; 0% 7307x1056 jgcfinaderfiyad4w Filed Feb. 14, 1955 United States Patent 2,918,171 TRANSFER AND COMMINUTING DEVICE Carl H. Nordell, Crystal Bay, Nev. Application February 14, 1955, Serial No. 488,053 9 Claims. (Cl. 210159) This invention relates to a transfer and comminuting device, and more particularly to means for transferring solids intercepted by a screen in a flowing stream of sewage to a comminuting device for comminution.

In accordance with the present invention an inclined screen extending across the influent channel intercepts all solids too large to pass therethrough. A cutting cylinder is rotatably mounted above the screen and adjacent the upper end of the screen. The screen is provided with longitudinally aligned, spaced screen bars, and the cutting cylinder is provided with laterally projecting means adapted to carry solids from the surface of the screen to the vicinity of a comb. A plurality of teeth projecting laterally from the periphery of the cutting cylinder cooperate with the comb to comminute the solids that are interengaged by the teeth and the comb.

The present invention contemplates the provision of means in combination with the screen and cylinder to periodically sweep or rake the screen and transfer the intercepted solids from the remote areas of the screen to the area of the screen adjacent the cylinder as modified in accordance with the present invention, so that means projecting laterally from the cylinder may reach the solids and carry them to the cutting comb for comminution.

In order to bring the cutting cylinder and the solids together it has been proposed to have the cutting cylinder reciprocate in a longitudinal or horizontal direction adjacent the screen surface so that the entire surface area of the screen is periodically swept by the cutting cylinder. This type of structure has proved to be satisfactory in operation, but is relatively costly to make and is gen erally not feasible for small operations.

Another method is to provide a hopper beyond and below the upper end of the screen, and to move fingers longitudinally of the screen to push the solids into the hopper. The cutting cylinder forms one wall of the hopper and is adapted to pick the solids from the hopper and transfer them to the comminuting zone. The apparatus operating in accordance with this method is disclosed and claimed in my c-opending application filed April 19, 1954, under Serial No. 424,014.

It has also been proposed to provide the cutting cylinder with laterally projecting tines as disclosed and claimed in my Patent No. 2,750,044, issued June 12, 1956, on my copending application filed December 17, 1951, under Serial No. 261,973. In this structure tines project from the cutting cylinder and rotate therewith. The tines are extended their maximum distance as they pass upwardly through the screen and are gradually retracted as they approach the comb positioned adjacent the uppermost surface of the cylinder. As the tines pass through the screen they lift solids intercepted by the screen, and these solids move downwardly towards the cutting cylinder by gravity as the tines are rotated upwardly. The necessity of retracting the tines as they pass the comb imposes a limitation on the maximum length of the tines and, as a consequence, the tines cannot ex- Patented Dec. 22, 1959 tend far enough to remove the solids from the entire surface of the screen.

The present invention contemplates the provision of a simple, inexpensive rake capable of engaging solids intercepted by the screen in areas remote from the cutting cylinder, and moving the solids upwardly along the upper surface of the screen into the area adjacent the cutting cylinder. Means projecting laterally from the periphery of the cutting cylinder pick up the solids intercepted by the screen within the area reached by such means and the solids moved into this area by the rake. The cutting cylinder carries the solids to the area adjacent the comb and the teeth of the cutting cylinder cooperate with notches in the comb to comminute the solids. The device of the present invention is particularly suitable for use in sewage operations in small cities and towns where the amounts of sewage to be treated are relatively small.

The rake is mounted below the screen, and is provided with a plurality of upstanding posts which project from the underside of the screen into the spaces between adjacent screen elements. The rake posts are projected above the upper surface of the screen when the rake is being moved towards the cutting cylinder to enable them to move the solids intercepted by the screen upwardly along the screen surface. When the rake is moving downwardly away from the cutting cylinder the rake posts are retracted below the upper surface of the screen, to prevent them from moving the solids intercepted by the screen downwardly along the screen.

The structure by which the above mentioned and other advantages of the invention are attained will be described in the following specification, taken in conjunction with the accompanying drawings, showing a preferred illustrative embodiment of the invention, in which:

Figure l is a fragmentary perspective view of a channel through which sewage flows, an inclined screen extending across the channel with its screen bars spaced transversely, a rake having posts extending between the screen bars, and a comminuting device mounted adjacent the upper end of the screen all in accordance with the present invention;

Fig. 2 is a side view, partly in elevation and partly in section, showing the rake and the means for moving it along the screen to move solids intercepted by the screen in the area remote from the cutting cylinder to the area adjacent the cutting cylinder;

Fig. 3 is a fragmentary longitudinal sectional view, showing the rake at the end of its upward movement in solid lines and at the end of its forward movement in dotted lines;

Fig. 4 is a fragmentary perspective view and the means for moving it;

Fig. 5 is a fragmentary view, partly in elevation and partly in section, showing the rake and the means for positioning it relative to the screen;

Fig. 6 is a cross-sectional view, 66 of Fig. 5;

Fig. 7 is a cross-sectional view, 7-7 of Fig. 5; and

Fig. 8 is a longitudinal sectional view, line 8-8 of Fig. 7.

In the drawings, reference numeral 2 indicates an influence channel through which flows unscreened sewage carrying solids, and 3 indicates the efilucnt channel through which the screened sewage flows along with the solids that are comminuted adjacent the upper end of the screen on which they accumulate. Channels 2 and 3 are parts of a single structure, preferably made of. concrete.

A screen 4 is supported in inclined position in channel 2 by means of a pair of standards 5 extending upwardly from the bottom of the channel. Any form of screen may be used. The illustrative embodiment of the screen of the rake taken along the line taken along the line taken along the shown in the drawings comprises a plurality of flat metal ribbons disposed on the edges and held in transversely spaced relationship. Suitable supports extending laterally from the side walls of the channel can be used instead of standards 5, if desired. The lower end of the screen can be secured to the bottom of channel 2 in any suitable manner. The screen is illustrated as being inclined at approximately thirty degrees, but it will be understood that this angle may be varied, as desired.

Screen 4 comprises a frame 6 the outer edges of which are flush against the walls of influent channel 2. Frame 6 is provided with a centrally disposed opening 7 across which a plurality of individual screen elements 8 extend. These screen elements are disposed edgewise and longitudinally of the screen, and are transversely spaced across the space between the longitudinal edges of frame 6. The screen elements are held under tension by any suitable means, such as the tensioning device described and claimed in my Patent No. 2,727,627, issued December 20, 1955, on my copending application filed March 26, 1954, under Serial No. 418,944. The edgewise disposition of individual screen elements in a screen is disclosed in Patent No. 2,750,044.

A hollow cutting cylinder 9, disposed horizontally relative to the screen, is rotatably mounted in bearings contained within housing 10 supported on brackets 11 secured to the upper surface of frame 6. The cutting cylinder is provided at one end with a housing 12 which contains gears (not shown) operatively connected to a motor 13 for rotating the cylinder. Cylinder 9 is provided with a plurality of series of laterally extending teeth 14 and retractable tines 15. The teeth and tines are spaced longitudinally of the cylinder to coincide with the spacing between individual screen elements so that teeth 14 enter the spaces between adjacent screen elements 8 as the cylinder rotates. As described in Patent No. 2,750,044, the tines pass through the spaces between adjacent screen elements when they are in extended position, and are retracted automatically as the rotation of the cylinder moves them upwardly.

Tines 15 are each secured at one end to a bar 16 horizontally disposed within cutting cylinder 9. The tines are alternately arranged so that half of them extend in one direction at right angles to one surface of bar 16, and the other half extend in the opposite direction. Crank arms 17 pivotally mounted adjacent opposite ends of cylinder 9, as indicated at 18, are each secured to one end of bar 16 so that as the cylinder is rotated bar 16 moves along the diameter of the cylinder and one set of tines moves inwardly as the other set moves outwardly of the cylinder. Opposite sides of the cylinder are provided with apertures 19 through which the tines project.

A stationary comb 20, secured to housings 10 and 12, extends parallel to the longitudinal axis of cutting cylinder 9, and is positioned adjacent the peripheral surface of the cylinder along a line spaced radially from the line of contact between said tines and screen elements 8. Comb 20 is provided with longitudinally spaced notches or recesses 21 aligned with teeth 14 which eooperate to comminute solids carried by the teeth as they pass through the notches. The tines on one side of bar 16 are retracted so that they are entirely within the cutting cylinder as they pass comb 20. In this position the tines on the other side of the bar are projected their maximum distance from the cylinders, into the spaces between the screen elements.

The solids that are intercepted by the screen Within the area reached by tines 15 are engaged by the tines and lifted until they fall by gravity into contact with the cutting cylinder. These solids are then engaged by teeth 14 and carried by said teeth along the portion of the periphery of cutting cylinder 9 to the comb. The solids remain against the comb until they are forced through notches 21. In being so forced the solids are comminuted, and pass through the screen and into effluent channel 3 along with the flowing sewage stream that has passed through the screen. In the operation of the device the rotation of cylinder 9 is continuous, thus aiding in effecting comminution continuously.

A transfer device or rake, adapted to be reciprocated longitudinally of the screen, is provided for the purpose of moving solids that are intercepted by the portion of the screen remote from the cutting cylinder upwardly along the screen into the area adjacent the cutting cylinder. The transfer device comprises a plurality of short posts 22 secured in transversely spaced relationship to a bar 23 positioned below the screen. In the embodiment illustrated, bar 23 is in the form of an angle iron, but it will be understood that it may be of any desired shape. Each post is positioned between adjacent screen elements 8 and is of substantially the same thickness as the distance between adjacent screen elements so that the posts will wipe the screen elements clean as they are moved longitudinally of the screen in their upwardly projecting position.

The structure at opposite longitudinal edges of screen frame 6 is the same and, therefore, the structure on only one side will be described. The longitudinal edge of screen frame 6 is provided with a downwardly extending flange 24 fitting against the adjacent wall of channel 2. A guide channel 25 is rigidly secured to flange 24 with its side walls 26 and 27 extending inwardly. A longitudinally extending plate 28 positioned adjacent the inner edges of sidewalls 26 and 27 has secured to its outer surface a pair of spaced blocks 29 slidably fitting within guide channel 25. Blocks 29 may be formed of metal, plastic, or the like.

A bell crank 30 is pivotally secured to plate 28, as indicated at 31. The ends of bar 23 are each welded to one end of bell crank 3. An angular strip 32 is secured at its ends, by welding or other suitable means, to plates 23. Strip 32 has one section 33 adapted to overlie the top surface of bar 23 in substantial parallelism. Section 33 is provided with a series of transversely spaced apertures 34 adapted to fit loosely over posts 22 to permit slight angular movement of the posts relative to strip 32 when bell crank 30 moves pivotally, as hereinafter described.

The other end of bell crank 30 is secured to one end of a rod 35, as indicated at 36. The upper end of plate 28 is secured to a rod 37, as indicated at 38. Rods 35 and 37 pass through apertures in a transverse bar 39 which guide the rods in a straight line movement. Rod 37 is secured at its upper end to a transverse bar 40, and rod 35 is similarly secured at its upper end to a similar bar 41. Bar 41 is secured to one end of a piston rod 42 reciprocable by a power cylinder 43 operated by a hydraulic system including lines 44 and 45 which lead to and from a pump (not shown). Bar 40 is secured to one end of a piston rod 46 mounted at one end in a retarding cylinder 47. Cylinder 47 has interconnected lines 48, 49 leading to its opposite ends and having a bypass valve 50 therebetwecn.

Cylinder 47 is provided with a piston (not shown) to which rod 46 is fixed at one end. Cylinder 47 is substantially filled with oil or other suitable fluid. When the rake is at the forward end of screen 4 the piston is at the forward end of cylinder 47. A similar piston (not shown) which is connected to one end of piston rod 42 is positioned in the forward end of cylinder 43. The pump (not shown) pulls fluid out of the upper part of cylinder 43 through outlet 44 and forces fluid into the lower part of cylinder 43 through inlet 45 to move the piston upwardly and thereby, through the operative connections with piston rod 42, bar 41 and rod 35, moves the rake upwardly along the screen. The upward movement of rod 35 tends to pull plate 28 upwardly, but this move ment is at first resisted by rod 37 because its piston is pressing against the fluid in cylinder 47. The restriction of valve 50 lets the fluid pass from the upper portion of cylinder 43 to the lower portion comparatively slowly, with the result that rod 35 stirts moving upwardly before rod 37.

While rod 37 holds plate 28 against upward movement rod 35 starts moving upwardly and pulls bell crank 30, to which it is secured, around pivot 31 before plate 28 starts moving upwardly. This pivotal movement of bell crank 30 moves post carrying bar 23 from the position shown in dotted lines in Fig. 3 to the position shown in solid lines in Fig. 2. During this initial movement angular strip 32, which is fixed to plate 28, remains stationary. By the time bar 23 has moved pivotally as far as possible, enough fluid has passed from the upper portion of cylinder 47 through line 48, valve 50, and line 49 to permit rod 46 to start moving upwardly. Valve 50 is adjusted so that piston rod 46 moves at the same rate as piston rod 42 so that plate 28 and bell crank 30, which carry strip 32 and bar 23, respectively, move upwardly longitudinally of the screen with posts 22 projecting through spaces between adjacent screen elements 8. In this position posts 22 wipe the screen clean and move solids intercepted by the screen upwardly along its upper surface. The force of the flowing stream of sewage helps move the solids along the inclined screen.

As the rake appraches the position shown in solid lines in Fig. 3, which indicates the upper limit of travel, tines 15, which rotate upwardly through the spaces between adjacent screen elements as cutting cylinder 9 rotates, lift the solids from the screen and carry them upwardly. As tines move upwardly past a horizontal plane the solids slide downwardly by gravity into engagement with cylinder 9. Teeth 14 projecting laterally from cylinder 9 engage these solids and carry them upwardly into engagement with comb 20, where they are comminuted by the cooperation of teeth 14 and slots 21 of the comb. The comminuted solids fall through screen 4 into efiluent channel 3 to flow with the screened sewage for further treatment.

The fiow of fluid relative to cylinder 43 is reversed automatically by any suitable means when the rake reaches the position shown in solid lines in Fig. 3. The fluid in cylinder 47 again retards the movement of piston rod 46 temporarily, until bell crank 30 is moved pivotally to bring the upper edges of posts 22 below the upper surface of the screen, so that when the rake starts its downward movement posts 22 will not move any of the solids intercepted by the screen downwardly. Piston rod 46 starts its downward movement after bell crank 30 has been moved pivotally downwardly to the position shown in dotted lines in Fig. 2. Thereafter the flow of fluid through valve 50 causes piston rod 46 to move downwardly at the same rate as piston rod 42.

While I have described a preferred embodiment of my invention in considerable detail, it will be understood that the description thereof is intended to be illustrative, rather than restrictive, as many details may be modified or changed without departing from the spirit or scope of the invention. Accordingly, I do not desire to be restricted to the exact construction described.

I claim:

1. In combination with a comminuting device, a screen comprising a frame and a plurality of longitudinally extending, parallel, screen elements spaced uniformly transversely of said frame, said frame having a longitudinal edge portion provided with a pair of vertically spaced inwardly extending parallel ribs, a rake comprising a bar extending transversely of said screen and a plurality of posts extending upwardly from said bar, said posts being of a width substantially equal to the space between adjacent screen elements and spaced to fit within said spaces, a block fitting between said ribs, said block being rigidly secured to a plate, a bell crank pivotally mounted on said plate, said bell crank being rigidly secured to said bar, and a rod connected to said bell crank, said rod being operable to reciprocate said rake, thereby moving said posts longitudinally of said screen elements to transfer solids from the surface of the lower portion of said screen to a predetermined area intermediate the length of said screen.

2. In combination with a comminuting device, a screen comprising a frame and a plurality of longitudinally extending, parallel, screen elements spaced uniformly transversely of said frame, said frame having a longitudinal edge portion provided with a pair of vertically spaced inwardly extending parallel ribs, a rake comprising a bar extending transversely of said screen and a plurality of posts extending upwardly from said bar, said posts being of a width substantially equal to the space between adjacent screen elements and spaced to fit within said spaces, a block fitting between said ribs, said block being rigidly secured to a plate, a bell crank pivotally mounted on said plate, said bell crank being rigidly secured to said bar, and a longitudinal rod connected to said bell crank, said rod being operable to reciprocate said rake. thereby moving said posts longitudinally of said screen elements to transfer solids from the surface of the lower portion of said screen to a predetermined area intermediate the length of said screen, means to move said posts to position their upper ends above the upper surface of said screen with said posts disposed angularly relative to said screen to facilitate transfer of solids to said predetermined intermediate area when said posts are moved longitudinally of said screen toward said intermediate area, and means to position the upper ends of said posts below the upper surface of said screen to prevent movement of solids in the opposite direction when said posts are moved longitudinally of said screen away from said intermediate area.

3. In combination, a screen comprising a plurality of longitudinally extending, spaced, parallel, screen elements adapted to be interposed in a flowing stream of sewage for intercepting solids in said sewage, a comminuting device positioned directly above said screen and adjacent one end of said screen, said comminuting device including a rotatable cylinder having a plurality of laterally projecting retractable tincs movable between adjacent screen elements upon rotation of said cylinder and a plurality of laterally projecting teeth, means to rotate said cylinder, means to retract and project said tines as said cylin der rotates, and a comb spaced from said screen and in proximity to said cylinder, a rake comprising a bar extending transversely of said screen and a plurality of posts extending upwardly from said bar, said posts being spaced to fit within the spaces between said screen elements, said rake being movable longitudinally of said screen to and from the bottom of said screen elements and a region adjacent the projecting length of said tines, to transfer solids intercepted by said screen along the surface of said screen to said region, and means to move said rake, whereby said tines lift solids from said region upon rotation of said cylinder and guide them into engagement with said teeth, rotation of said cylinder moving said teeth into cooperating relationship with said comb to comminute said solids, means to elevate said posts above the upper surface of said screen at the bottom of said screen and to depress said posts below the upper surface of said screen at the said region, whereby said rake transfers intercepted solids only in its movement from the bottom of said screen to said region.

4. In combination, a screen comprising a frame having downwardly extending flanges at its longitudinal edges and a plurality of longitudinally extending, spaced, parallel, screen elements, a pair of vertically spaced ribs extending inwardly from each of said flanges, a bar extending transversely of said screen, a plurality of posts projecting upwardly from said bar and extending between adjacent screen elements, a block slidably mounted between each pair of ribs, each of said blocks being rigidly secured to a plate, a bell crank pivotally mounted on each of said plates, said bell cranks being rigidly secured to opposite ends of said bar and each connected to a longitudinal rod operable to reciprocate said blocks simultaneously longitudinally of said screen, whereby said posts may be moved between said screen elements longitudinally of said screen, and means to move said rods.

5. In combination, a screen adapted to be interposed in a flowing stream of sewage for intercepting solids in said sewage, and a comminuting device positioned directly above said screen and adjacent one end of said screen, said comminuting device comprising a rotatable cylinder having a plurality of laterally projecting teeth, means to rotate said cylinder, and a comb spaced from said screen and in proximity to said cylinder, said screen comprising a frame having downwardly extending flanges at its longitudinal edges and a plurality of longitudinally extending, spaced, parallel, screen elements, a pair of vertically spaced ribs extending inwardly from each of said flanges, a bar extending transversely of said screen, a plurality of posts projecting upwardly from said bar and extending between adjacent screen elements, a block slidably mounted between each pair of ribs, each of said blocks being rigidly secured to a plate, a bell crank pivotally mounted on each of said plates, said bell cranks being rigidly secured to opposite ends of said bar and each connected to a longitudinal rod operable to reciprocate said blocks simultaneously longitudinally of said screen, whereby said posts may be moved longitudinally between said screen elements of said screen to transfer solids intercepted by said screen along the upper surface of said screen to an area spaced from said cylinder, means to move said rods, and separate means operable on rotation of said cylinder to engage said solids transferred by said posts to lift said solids from said screen and guide them into engagement with said teeth, rotation of said cylinder moving said teeth into cooperating relationship with said comb to comminute said solids.

6. In combination, a screen comprising a frame having downwardly extending flanges at its longitudinal edges and a plurality of longitudinally extending, spaced, parallel, screen elements, a pair of vertically spaced ribs extending inwardly from each of said flanges, a bar extending transversely of said screen, a plurality of posts projecting upwardly from said bar and extending between adjacent screen elements, a block slidably mounted between each pair of ribs, each of said blocks being rigidly secured to a plate, a bell crank pivotally mounted on each of said plates, said bell cranks being rigidly secured to opposite ends of said bar, an angular strip rigidly secured at its opposite ends to said plates, said strip having a series of apertures fitting loosely over said posts, each of said bell cranks being connected to a longitudinal rod operatively connected to a piston whereby said bar may be reciprocated longitudinally relative to said screen, means to move said piston, and retarding means automatically holding said plates from longitudinal movement at each change of direction of said piston until said bell cranks have moved pivotally relative to said plates, thereby causing said posts to move upwardly above the uppersurface of said screen before said bar starts its longitudinal movement towards the rear end of said screen and downwardly below the upper surface of said screen before said bar starts its longitudinal movement towards the forward end of said screen.

7. In combination, a screen comprising a plurality of longitudinally extending, spaced, parallel, screen elements adapted to be interposed in a flowing stream of sewage for intercepting solids in said sewage, a comminuting device positioned directly above said screen adjacent one end of said screen, said comminuting device including a rotatable cylinder and a comb, means to rotate said cylinder, means projecting laterally from said cylinder, said laterally projecting means being engageable with said screen elements to lift said solids from the area of the surface of said screen adjacent said rotatable cylinder, means on said cylinder to transfer said solids to said comb for comminution, a plurality of posts extending upwardly between adjacent screen elements, means to move said posts longitudinally of said screen, means to project said posts beyond the upper surface of said screen during longitudinal movement of said posts towards said cylinder, whereby said posts move solids intercepted by said screen in areas remote from said cylinder upwardly along the surface of said screen into an area adjacent said cylinder, and means to retract said posts below the upper surface of said screen during longitudinal movement of said posts away from said cylinder.

8. In combination, a screen comprising a plurality of longitudinally extending, spaced, parallel screen elements adapted to be interposed in a flowing stream of sewage for intercepting solids in said sewage, a comminuting device positioned directly above said screen and adjacent one end of said screen, a rake positioned below said screen, said rake having a plurality of posts projecting upwardly into the spaces between adjacent screen elements, means for reciprocating said rake longitudinally of said screen, means to project said posts upwardly beyond the upper surface of said screen during longitudinal movement of said rake towards said comminuting device, and means to retract said posts below the upper surface of said screen during longitudinal movement of said rake in the opposite direction.

9. In combination, a screen comprising a plurality of longitudinally extending spaced, parallel screen elements adapted to be interposed in a flowing stream of sewage for intercepting solids in said sewage, a comminuting device positioned directly above said screen and adjacent one end of said screen, rotatable means for removing solids from an area of said screen adjacent said comminuting device and transferring them to said comminuting device, a rake positioned below said screen and having retractible posts extending into the spaces between adjacent screen elements, and means for moving said rake longitudinally of said screen to move solids intercepted by said screen in areas of said screen remote from said rotatable means upwardly along the surface of said screen into said first mentioned area.

References Cited in the file of this patent UNITED STATES PATENTS 2,106,851 Nordell Feb. 1, 1938 2,781,915 Wormser Feb. 19, 1957 FOREIGN PATENTS 459,756 Great Britain Jan. 14, 1937 120,108 Australia June 22, 1945 

